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mine did the same thing after sitting for a while. i hit it with starting fluid and it has started fine every since. not sayin this will help but just puttin it out there. make sure the grounds are good. the fuel pump is grounded to the tank/body. if you dont have a good ground from the battery to the body or the engine to the body. (been there too)

battery is good had a charger hooked up to it. wish this was the problem.
good grounds
all wires good
gonna check relay and fuse next.
and pcm bad??? hows this happen and how offten. do they just self destruct or what?

battery is good had a charger hooked up to it. wish this was the problem.
good grounds
all wires good
gonna check relay and fuse next.
and pcm bad??? hows this happen and how offten. do they just self destruct or what?

whats the omh's suppose to be on the cps when you check it?

The PCM runs the pump for threee seconds after turning ignition key to ON. PCMs rarely fail, but it happens.

most likely culprit on a '90 is a bad ballast resistor. it's white, made of ceramic, long with an offset bolt holding it to the inner fender wall. either located toward the drivers side of the air box, or farther back, same side, near the firewall.

make a jumper wire using two male spade connectors. bypass the resistor, and goop up the ends with some dialectirc grease. then tape over the ends, and never look back.

take two wires attatched to a 12v battery, climb under the jeep, disconnect the fuel pump, connect negative to black, and positive to the other large wire (green, purple, or orange...can't remember lol). if that makes the pump come on, your issue is elsewhere...try replacing the relays near the battery, then start checking the fusible links with a test light.

Did a new pump make the fix? I'm having nearly an identical problem but after 2 new pumps, and trying to make them run by wiring them direct..still not running.
Going to take the latest new one out and bench test it. Been two months dicking with this problem.....grr...